Posts by Anthony Horton

Square Kilometre

The square kilometre in the name Square Kilometre Array refers to the total collecting area of all the dishes rather than the amount of land area required to site them all, so it's not that misleading really.

While Manchester Uni/Jodrell Bank have a lot of experience with this sort of thing it still seems a surprising choice for the the location of the SKA HQ as it's going to be built (assuming it can keep the funding going) either in South Africa or Western Australia. Being in Manchester would make it a bit difficult to pop out of the lab to check on the progress of the building work, but more to the point if you were a radio astronomy boffin where would you want your office sited? Manchester or Perth?

@ Ru & Adam Azarchs

Firstly, on the important issue at hand, I'm firmly in the pro-boffin camp. Now the science bit:

The record-breakingly superficial BBC article doesn't make it clear but 'lucky imaging' has in fact been in use by professional astronomers for a while (for approximately of a decade I'd say, the Cambridge University astronomers were already doing it in 2000 when I was working with them), and the technique has since filtered down to amateur astronomers. Adaptive optics isn't new either, as Ru says all the major observatories now use it (though the primary mirrors do not in fact do the correction for the atmosphere, the actuated primaries of modern telescopes handle slow distortions of the telescope whereas the atmospheric distortions are still taken out by smaller, faster moving mirrors downstream). What's actually new is combining lucky imaging and adaptive optics, which gives better images than either technique alone. Without adaptive optics lucky imaging is only really effectively on small(ish) telescopes, say 1-2m diameter, because the larger the telescope the greater the effect of the atmospheric distortions and the luckier you have to be to get a sharp image. With adaptive optics though the distortions are much reduced and a worthwhile fraction of the images are sharp even on a larger telescopes such as the Palomar 200", which have intrinsically higher resolution. Both techniques need a bright star near what you want to look at as you need something visible in very short individual exposures to tell whether the image is sharp/measure the atmospheric distortions, but you can partially get around that limitation by attaching frikkin' lasers to your telescope.